Food product cabinet system and method for antimicrobial treatment of food products

ABSTRACT

Apparatuses and methods for applying an antimicrobial agent to food products include methods and systems for limiting the escape of antimicrobial agent to the environment during antimicrobial treatment of the food product. In one embodiment, a series of cabinet panels moves in line with the passing food product and forms an enclosure around the food product by means of panels closing ahead of and behind the food product. In another embodiment, the direction and spray pattern of positively charged aerosolized antimicrobial particles is controlled by attracting the particles to preselected negatively charged regions within a treatment volume.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.16/279,525 filed Feb. 19, 2019 (now U.S. Pat. No. 10,531,669, issuedJan. 14, 2020), which is a continuation-in-part of U.S. patentapplication Ser. No. 15/255,897, filed Sep. 2, 2016 (now U.S. Pat. No.10,206,407, issued Feb. 19, 2019), which claims the benefit of U.S.Provisional Patent Application 62/214,729, filed 4 Sep. 2015, the entiredisclosures of both of which are incorporated herein by reference.

FIELD OF THE INVENTION

This disclosure relates to apparatuses, methods, and systems forapplying an antimicrobial treatment agent to a food product, and inparticular to food products cabinets therefor.

DESCRIPTION OF THE RELATED ART

Currently, the most commonly used method for antimicrobial treatment ofanimal carcasses is hot water pasteurization. Hot water pasteurizationis a “flood” technology, relying on a large volume of water to ensurethat each carcass is fully covered or surrounded and exposed to heatacross its entire surface to reduce the levels of pathogens. One commontype of pasteurization “cabinet” known in the art is a one-piececabinet, comprising a portion that encloses one or more carcasses tohold steam. The one-piece cabinet moves forward and back, in a straightline, to enclose the carcass.

One-piece cabinets suffer from a number of drawbacks. The number ofintervention technologies and practices that can be used in conjunctionwith a one-piece cabinet is strictly limited. One-piece cabinets canalso be dangerous to workers in the immediate proximity of the cabinet.Furthermore, it can be difficult to assess and ensure complete coverageof the carcass with an intervention or treatment agent.

There is thus a long-felt need for devices, systems, and methods forantimicrobial treatment of animal carcasses that allows a wider range ofintervention technologies and practices while safeguarding workerwelfare. It is advantageous for such devices, systems, and methods toreliably ensure that the entire surface of the carcass is covered orsurrounded by an intervention or treatment agent. It is furtheradvantageous for such devices, systems, and methods to be applicable toantimicrobial treatment of food products other than animal carcasses,including but not limited to produce such as fruits and vegetables.

BRIEF SUMMARY OF THE INVENTION

It is one aspect of the present invention to provide a method forantimicrobial treatment of food products, comprising:

a) aerosolizing a liquid antimicrobial agent to form aerosolizedantimicrobial particles;

b) imparting a positive charge to the aerosolized antimicrobialparticles;

c) spraying the aerosolized antimicrobial particles into a treatmentvolume;

d) placing at least one food product at least partially within thetreatment volume such that at least a first portion of the aerosolizedantimicrobial particles adheres to a surface of the at least one foodproduct to form a substantially uniform layer of the antimicrobialagent;

e) imparting a negative charge to at least one evacuation region withinthe treatment volume to attract at least a second portion of theaerosolized antimicrobial particles into the at least one evacuationregion; and

g) evacuating substantially all of the aerosolized antimicrobialparticles within the evacuation region from the treatment volume.

In embodiments, the at least one food product may comprise a wholeanimal carcass. The whole animal carcass may, but need not, comprise awhole bird carcass.

In embodiments, the at least one food product may comprise a portion ofa carcass of an animal that has been cut, split, or otherwise separatedfrom a remainder of the carcass. The animal may, but need not, be abird.

In embodiments, the at least one food product may comprise at least onefruit or vegetable.

In embodiments, the aerosolized antimicrobial particles may have anaverage diameter of less than about 60 microns.

In embodiments, an attractive force between the surface of the at leastone food product and the layer of the antimicrobial agent may be equalto about 75 times the force of gravity.

These and other advantages will be apparent from the disclosurecontained herein.

For purposes of further disclosure and to comply with applicable writtendescription and enablement requirements, the following referencesgenerally relate to systems and methods for antimicrobial treatment offood products and for related systems and methods, and are herebyincorporated by reference in their entireties:

U.S. Pat. No. 4,852,216, entitled “Animal slaughtering chemicaltreatment and method,” issued 1 Aug. 1989 to Clayton et al. (“ClaytonI”). Clayton I describes a material and method for processing meat inproduction in which the meat, both carcass and head, which can proceedon different production lines, is rinsed and treated with acetic acidafter hide removal. The water and acid are maintained at a temperatureof between 80 and 150° F. The acid is in a water-based solution atconcentrations ranging from 0.25% to 2.00%. After evisceration for thecarcass and removal of waste from the head, the head and carcass arerinsed and treated with acetic acid again before being sent to coldstorage, from which they are released later for further processing. Thefirst rinsing step is commenced within one hour of the time the hide isremoved from the animal.

U.S. Pat. No. 4,862,557, entitled “Animal slaughtering chemicaltreatment and method,” issued 5 Sep. 1989 to Clayton et al. (“ClaytonII”). Clayton II describes a material and method for processing meat inproduction in which the meat, both carcass and head, which can proceedon different production lines, is rinsed and treated with acetic acidafter hide removal. The water and acid are maintained at a temperatureof between 80 and 150° F. The acid is in a water-based solution atconcentrations ranging from 0.25% to 2.00%. After evisceration for thecarcass and removal of waste from the head, the head and carcass arerinsed and treated with acetic acid again before being sent to coldstorage, from which they are released later for further processing. Thefirst rinsing step is commenced within one hour of the time the hide isremoved from the animal.

U.S. Pat. No. 5,374,433, entitled “Method for preserving food products,”issued 20 Dec. 1994 to Bowling et al. (“Bowling I”). Bowling I describesa method for preserving a food product, such as meat. The methodcomprises the steps of inoculating meat with an effective amount ofeuhygienic non-pathogenic, non-spoilage bacteria in order tocompetitively inhibit the growth of undesired pathogenic and spoilagebacteria. Preferably, either L. delbrueckii or Hafnia alvei bacteria areused to inoculate a meat product. Bacteria present on a meat product arefirst reduced to a number below about 5,000 bacteria per gram of meat,e.g. by dehairing an animal and then spraying the meat with an organicacid prior to inoculation with euhygienic bacteria. The meat product isthen vacuum packaged and stored in a refrigerated environment of about−1° C. to about 7° C. Meat products preserved in accordance with themethod of the invention can enjoy a refrigerated shelf life of up toabout 150 days without surface discoloration or the generation ofundesirable gaseous byproducts.

U.S. Pat. No. 5,576,035, entitled “Method for preserving food productsand food products made thereby,” issued 19 Nov. 1996 to Bowling et al.(“Bowling II”). Bowling II describes a method for preserving a foodproduct, such as meat. The method comprises the steps of inoculatingmeat with an effective amount of non-pathogenic, non-spoilage bacteriain order to competitively inhibit the growth of undesired pathogenic andspoilage bacteria. Preferably, either L. delbrueckii or Hafnia alveibacteria are used to inoculate a meat product. Bacteria present on ameat product are first reduced to a number below about 5,000 bacteriaper gram of meat, e.g. by dehairing an animal and then spraying the meatwith an organic acid prior to inoculation with bacteria. The meatproduct is then vacuum packaged and stored in a refrigerated environmentof about −1° C. to about 7° C. Meat products preserved in accordancewith the method of the invention can enjoy a refrigerated shelf life ofup to about 150 days without surface discoloration or the generation ofundesirable gaseous byproducts.

U.S. Pat. No. 5,853,320, entitled “Plucking apparatus for poultry,”issued 29 Dec. 1998 to Wathes et al. (“Wathes”). Wathes describes aplucking apparatus for plucking poultry carcasses on a shackle lineincluding a plurality of individual plucking units, one for each of anumber of carcasses to be plucked at any one time, and shielding meansincluded in or provided additionally to said plucking units, whereby theplucking heads of each said unit are shielded from the plucking heads ofthe neighboring units during plucking.

U.S. Pat. No. 5,869,113, entitled “Method for preserving food productsand food products made thereby,” issued 9 Feb. 1999 to Clayton et al.(“Clayton III”). Clayton III describes a method for preserving a foodproduct, such as meat, using the steps of inoculating meat with aneffective amount of euhygienic non-pathogenic, non-spoilage bacteria inorder to competitively inhibit the growth of undesired pathogenic andspoilage bacteria. Edible films that incorporate and/or cover euhygienicbacteria on the food product are used to ensure competitive inhibitionof undesired spoilage and pathogenic bacteria.

U.S. Pat. No. 5,980,375, entitled “Method and apparatus forantimicrobial treatment of animal carcasses,” issued 9 Nov. 1999 toAnderson et al. (“Anderson”). Anderson describes a two-stepantimicrobial treatment of animal carcasses prior to chill storage in acommercial slaughter operation. As a first step, the carcass is isolatedin a hot water pasteurization chamber and sprayed with recirculationwater at a temperature of at least 165° F. over its entire surface for atime sufficient to kill bacteria. Isolation is achieved with aircurtains across the entrance and exit openings, an exhaust system, and aliquid level control in the bottom of the chamber. Recirculation watercollected in the bottom of the chamber is filtered, combined with makeupwater, heated, and recirculated to the chamber. As a second step, thecarcass is isolated in an acid application chamber and sprayed with anorganic acid solution immediately prior to delivery to the chillstorage.

U.S. Pat. No. 6,039,984, entitled “Method for treating a food processingfacility,” issued 21 Mar. 2000 to Bowling et al. (“Bowling III”).Bowling III describes a method for preserving a food product, such asmeat, comprising the steps of inoculating meat with an effective amountof euhygienic non-pathogenic, non-spoilage bacteria in order tocompetitively inhibit the growth of undesired pathogenic and spoilagebacteria. Edible films that incorporate and/or cover euhygienic bacteriaon the food product are used to ensure competitive inhibition ofundesired spoilage and pathogenic bacteria.

U.S. Pat. No. 6,287,610, entitled “Method for increasing the tendernessof a meat product,” issued 11 Sep. 2001 to Bowling et al. (“BowlingIV”). Bowling IV describes a method for preserving a food product, suchas meat, including the steps of inoculating meat with an effectiveamount of euhygienic non-pathogenic, non-spoilage bacteria in order tocompetitively inhibit the growth of undesired pathogenic and spoilagebacteria. Edible films that incorporate and/or cover euhygienic bacteriaon the food product are used to ensure competitive inhibition ofundesired spoilage and pathogenic bacteria.

U.S. Pat. No. 6,569,474, entitled “System for preserving food products,”issued 27 May 2003 to Clayton et al. (“Clayton IV”). Clayton IVdescribes a method for preserving a food product, such as meat,including the steps of inoculating meat with an effective amount ofeuhygienic non-pathogenic, non-spoilage bacteria in order tocompetitively inhibit the growth of undesired pathogenic and spoilagebacteria. Edible films that incorporate and/or cover euhygienic bacteriaon the food product are used to ensure competitive inhibition ofundesired spoilage and pathogenic bacteria.

U.S. Patent Application Publication No. 2004/0052702, entitled “Foodproduct surface sterilization apparatus and method,” published 18 Mar.2004 to Shuman et al. (“Shuman”).

U.S. Pat. No. 6,742,720, entitled “Spray application system,” issued 1Jun. 2004 to Nolen (“Nolen I”).

U.S. Pat. No. 6,964,788, entitled “System for handling processed meatand poultry products,” issued 15 Nov. 2005 to Phebus et al. (“Phebus”).

U.S. Pat. No. 7,169,415, entitled “System for preserving fresh meatproducts,” issued 30 January 2007 to Bowling et al. (“Bowling V”).Bowling V describes a method for preserving a food product, such asmeat, comprising the steps of inoculating meat with an effective amountof euhygienic non-pathogenic, non-spoilage bacteria in order tocompetitively inhibit the growth of undesired pathogenic and spoilagebacteria. Edible films that incorporate and/or cover euhygienic bacteriaon the food product are used to ensure competitive inhibition ofundesired spoilage and pathogenic bacteria.

U.S. Patent Application Publication No. 2009/0081317, entitled“Microbiocidal control in the processing of meat-producing four-leggedanimals,” published 26 Mar. 2009 to McNaughton et al. (“McNaughton”).

U.S. Patent Application Publication No. 2009/0196967, entitled“Application system with recycle and related use of antimicrobialquaternary ammonium compound,” published 6 Aug. 2009 to Nolen et al.(“Nolen II”).

U.S. Patent Application Publication No. 2010/0093266, entitled “Machinefor scrubbing exterior of fowl and method of use thereof,” published 15Apr. 2010 to Chattin et al. (“Chattin”). Chattin describes a machine forscrubbing a fowl, wherein the machine comprises at least one pair ofopposing rotating brushes, wherein the fowl passes between said at leastone pair of opposing rotating brushes. The pair of opposing rotatingbrushes comprises a first rotating scrubber and a second rotatingscrubber having bristles extending therefrom. The fowl is suspended viaa shackle suspended from a track, wherein the height of the scrubbingmachine may be selectively varied via a threaded height adjuster. Thebristles of the machine are rotated, wherein the bristles contact theexterior of fowl traveling through the machine. Jets of water or othercleaning fluid spray inwardly to reach the fowl and the scrubbingbristles to rinse removed material from the fowl and bristles. Thebrushes are rotated through hubs attached to gears powered by a motor,wherein the gears may be selectively rotated in either direction.

U.S. Patent Application Publication No. 2011/0086146, entitled“Antimicrobial compositions for meat processing,” published 14 Apr. 2011to Knueven (“Knueven”). Knueven describes a method and composition forreducing microbes during a meat processing operation. The compositionincludes an acid blend that is a blend of (a) an organic acid selectedfrom the group consisting of lactic acid, acetic acid, and mixturesthereof, and (b) a second material selected from the group consisting ofalkali metal salts of inorganic acids, mineral acids, and mixturesthereof.

U.S. Patent Application Publication No. 2011/0136421, entitled “Cleaningapparatus and method,” published 9 Jun. 2011 to Brink et al. (“Brink”).Brink describes an apparatus and method for cleaning carcasses and adevice for mixing a cleaning substance that can be used in suchapplications. In some embodiments, the apparatus and method utilize amulti-phase cleaning substance spraying procedure in which the cleaningsubstance has desired levels of chlorine dioxide and is delivered to thecarcasses at desired flow rates, both of which can vary between phasesof the procedure and/or at different locations of the carcasses beingcleaned.

U.S. Patent Application Publication No. 2012/0225171, entitled “Methodfor controlling water content with decontamination in meats,” published6 Sep. 2012 to Garwood (“Garwood”). Garwood describes a method forproducing treated meat having a predetermined proportion of water in acontainer. The method includes treating meat that has lost water contentthrough evaporation with an agent capable of killing bacteria togetherwith an amount of water, wherein the amount of water corresponds to theamount of water that is lost through evaporation. The method providesmeat being treated with a bactericidal agent as well as providing meatwith the predetermined amount of water for packaging.

U.S. Patent Application Publication No. 2013/0231034, entitled “Methodand apparatus for processing livestock carcasses to destroymicroorganisms,” published 5 Sep. 2013 to O'Neil et al. (“O'Neil”).

U.S. Patent Application Publication No. 2014/0017364, entitled“Microbiocidal control in the processing of meat-producing four-leggedanimals,” published 16 Jan. 2014 to Liimatta (“Liimatta”). U.S. Pat. No.8,715,759, entitled “Method and apparatus for antimicrobial treatment ofmeat trimmings for subsequent grinding,” issued 6 May 2014 to Larson(“Larson”). Larson describes an antimicrobial intervention for theproduction of ground meats by treating the exterior of the meattrimmings with an antimicrobial agent before grinding. An apparatus forapplying an antibacterial agent to meat trimmings includes a closed oressentially closed chamber for limiting the escape of the antimicrobialagent to the environment during antimicrobial treatment of thetrimmings, an entrance system for introducing trimmings into the closedchamber while prevent or significantly limiting the antimicrobial agentfrom escaping into the environment, an application system for applyingan effective amount of the antimicrobial agent to exposed surfaces ofthe trimmings in the closed chamber, and an exit system for removing thetreated trimmings from the closed container while preventing orsignificantly limiting the escape of antimicrobial agent into theenvironment.

U.S. Patent Application Publication No. 2016/0088846, entitled“Antimicrobial compositions and methods of use thereof,” published 31Mar. 2016 to Lemons (“Lemons”).

U.S. Patent Application Publication No. 2016/0174585, entitled“Anti-microbial application equipment with controls,” published 23 Jun.2016 to Massey et al. (“Massey”).

U.S. Patent Application Publication No. 2017/0298407, entitled“Engineered water nanostructures (EWNS) and uses thereof,” published 19Oct. 2017 to Demokritou et al. (“Demokritou”).

U.S. Patent Application Publication No. 2017/0333914, entitled “Magneticcapture of a target from a fluid,” published 23 Nov. 2017 to Kang et al.(“Kang”).

As used herein, “at least one,” “one or more,” and “and/or” areopen-ended expressions that are both conjunctive and disjunctive inoperation. For example, each of the expressions “at least one of A, B,and C,” “at least one of A, B, or C,” “one or more of A, B, and C,” “oneor more of A, B, or C,” and “A, B, and/or C” means A alone, B alone, Calone, A and B together, A and C together, B and C together, or A, B,and C together.

It is to be noted that the term “a” or “an” entity refers to one or moreof that entity. As such, the terms “a” (or “an”), “one or more,” and “atleast one” can be used interchangeably herein. It is also to be notedthat the terms “comprising,” “including,” and “having” can be usedinterchangeably.

The embodiments and configurations described herein are neither completenor exhaustive. As will be appreciated, other embodiments of theinvention are possible utilizing, alone or in combination, one or moreof the features set forth above or described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a scale model of a prototype food producttreatment cabinet, according to embodiments of the present invention;

FIG. 2 is a side view of a scale model of a prototype food producttreatment cabinet, according to embodiments of the present invention;

FIG. 3 is a top view of a scale model of a prototype food producttreatment cabinet, according to embodiments of the present invention;

FIG. 4 is a bottom view of a scale model of a prototype food producttreatment cabinet, according to embodiments of the present invention;

FIG. 5 is a top view of a scale model of a prototype food producttreatment cabinet closure, according to embodiments of the presentinvention;

FIG. 6 is a perspective view of an exploded scale model of a prototypefood product treatment cabinet, according to embodiments of the presentinvention;

FIG. 7 is an illustration of a prior art apparatus for antimicrobialtreatment of meat products;

FIG. 8 is a side view of a food product treatment cabinet system,according to embodiments of the present invention; and

FIG. 9 is an overhead view of a food product treatment cabinet system,according to embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as is commonly understood by one of ordinary skillin the art. All patents, applications, published applications, and otherpublications to which reference is made herein are incorporated byreference in their entirety. In the event that there is a plurality ofdefinitions for a term herein, the definition provided in the BriefSummary of the Invention prevails unless otherwise stated.

As used herein, the term “animal carcass” is used to mean both a wholeanimal carcass, and any portion of a carcass of an animal which has beencut, split, or otherwise separated from a remainder of the carcass.

As used herein, the term “food product” is used to mean any animalcarcass or plant, or any portion of an animal carcass or plant, intendedto be eaten by a human or other animal. By way of non-limiting example,“food products” as that term is used herein include whole and splitanimal carcasses, fruits, and vegetables.

Referring now to FIGS. 1 through 6, an apparatus for applying anantimicrobial agent to a food product is illustrated. It is to beexpressly understood that, although the embodiment illustrated in FIGS.1 through 6 is adapted to apply an antimicrobial agent to a whole orsplit animal carcass and the description of FIGS. 1 through 6accordingly refers to “carcasses,” other embodiments of the inventionthat are not expressly illustrated in the accompanying drawings may beadapted to apply an antimicrobial treatment to food products other thananimal carcasses, including but not limited to produce such as fruitsand vegetables. It is to be further expressly understood that suchadditional and/or alternative embodiments are within the scope of thepresent invention.

The apparatus for applying an antimicrobial agent to whole or splitanimal carcasses illustrated in FIGS. 1 through 6 includes a closed oressentially closed chamber for limiting the escape of antimicrobialagent to the environment during antimicrobial treatment of the carcass.A series of carcass cabinet panels move in line with the passing animalcarcass and form an enclosure around the carcass by means of panelsclosing ahead of and behind the carcass. The center carcass cabinetpanel remains parallel to the carcass on either side of the movingcarcass. The leading and trailing carcass cabinet panels move the paneledged furthest from the center panel toward a position directly belowthe carcass main chain. Each carcass cabinet center panel, inconjunction with the attached forward and trailing panels, forms a180-degree enclosure around the target carcass. Two separate 180-degreeenclosures come together to form a single 360-degree enclosure thatsurrounds the carcass by carcass cabinet walls. The carcass cabinetcenter panels on either side of the carcass are bent at a 90-degreeangle toward the center chain at the top and bottom of the cabinetpanel. The carcass cabinet panels that lead and trail the center panelare also bent at a 90-degree angle toward the main chain. The cabinetpanel ends (including the upper and lower leading, center, and trailingpanels) form a closed end on the top and bottom of the 360-degreecarcass enclosure. The carcass hook attached to the main chain is theonly point at which the enclosure is not fully separated from theexterior environment. The hole in the top of the 360-degree enclosure,by means of some expansive or rubber material, is sealed to preventantimicrobial escape from around the carcass hook.

When the enclosure is fully sealed, nozzles installed toward the top ofboth center panels commence the antimicrobial application process. Theprocess fully covers the carcass by means of electrostatic nozzles thatcreate an attraction between the aerosolized antimicrobial agent and thecontained carcass.

Air-assisted electrostatic sprayers produce electrically charged spraydroplets of the antimicrobial agent, which are carried to the targetcarcass in an air stream. Electrical charges on the surface of the sprayparticles cause the particles to be attracted to the target carcass. Thecharged spray particles follow electric field lines around the targetcarcass, wrapping around the carcass and coating it on all sides.

The enclosed carcass chamber is then evacuated by means of a portlocated toward the lower end of the center cabinet panels. A source ofrelief air is drawn into the full enclosure through an upper port,allowing the chamber air, including the aerosolized antimicrobial, to beevacuated through the lower evacuation port.

When completely evacuated, the carcass cabinet begins the chamberseparation process, starting with the leading edge of the forward panel.The forward panels falls back to be in line with the center panel, asdoes the panel trailing the center panel. The three connected panels arethen parallel to the moving carcass. The panels then move along a routedefined by drive chains located at upper and lower contact points of thecarcass cabinet panel. The cabinet panel chains and connected panelsmake a 180-degree turn away from the moving carcass, toward the processstarting point, and then make a second 180-degree turn, toward the nextmoving carcass. The process then repeats.

The retractable carcass cabinet temporarily creates an individualchamber around each carcass while moving at speeds typical of anindustrial processing chain. The closed or essentially closed chamberallows for the use of a wide range of intervention technologies andpractices while safeguarding worker welfare in the immediate vicinity.

Electrostatic application of antimicrobial agents results inaerosolization of the antimicrobial agents, with particle sizes lessthan about 60 microns, and in some embodiments less than about 20microns. These particles receive an electrical charge from the spraynozzle, causing the particles to be attracted to the surface of thetarget carcass by a force about 75 times stronger than gravity. Thesmall particles adhere to the carcass in a highly uniform, thin layer,resulting in more complete coverage. The enclosure also allows forincreased concentrations of antimicrobial agents or other interventioncompounds, as the chamber prevents escape to the surrounding work area.

The retractable carcass cabinet enables continuous processing of largenumbers of animal carcasses, surrounding each carcass as it passes(while being driven by a carcass hook/chain), and then retracts awayafter treatment of each carcass.

Prior art apparatuses for antimicrobial treatment of meat products andother food products generally prevent charged particulate from escapingfrom an enclosure by means of physical barriers, typically in the formof revolving doors or evacuation of air, as illustrated in the twohighlighted portions of FIG. 7. In addition to necessitating additionalmoving parts, which are prone to wear and eventual failure, prior artapparatuses tend to give an operator little to no control over thedirection and spray pattern of charged particulate.

Referring now to FIGS. 8 and 9, in contrast to the prior art, foodproduct treatment systems of the present invention do not rely solely,and in some embodiments may not rely at all, on physical barriers toprevent charged particulate from escaping. As illustrated in FIGS. 8 and9, in food product treatment systems 10 of the present invention,electrostatic nozzles 11 are fixed on walls 12. In embodiments, thewalls 12 may be made of stainless steel; additionally and/oralternatively, walls 12 may be walls of a treatment cabinet, e.g. asillustrated in FIGS. 1 through 6, and/or may be fixed walls of a room orother chamber where food products are subjected to antimicrobialtreatment. In some embodiments, by way of non-limiting example, thewalls 12 may be interior surfaces of a processing building, a coldstorage facility, or a semi-trailer truck for transporting foodproducts.

Electrostatic nozzles 11 aerosolize a liquid antimicrobial agent andimpart a positive charge to the aerosolized antimicrobial particles. Inembodiments, the aerosolized antimicrobial particles may have an averagediameter of less than about 60 microns, and in some embodiments lessthan about 20 microns. As a result of their positive charge, theaerosolized antimicrobial particles are attracted to the surfaces offood products 13, which are driven, by a conveyor 14, through aninterior space defined by walls 12. The conveyor 14 may take anysuitable form, including but not limited to a motor-driven chain and/ora conveyor belt, and some embodiments may omit the conveyor 14altogether.

In embodiments, the attractive and/or adhesive force between thesurfaces of food products 13 and the aerosolized antimicrobial particlesmay be about 75 times the force of gravity. In the embodimentillustrated in FIG. 9, walls 12 may define an interior space sufficientto accommodate multiple food products 13 at the same time. The positivecharge of the aerosolized antimicrobial particles also serves todistribute the antimicrobial agent evenly over the surfaces of foodproducts 13.

Although the use of electrostatic nozzles to impart a positive charge onaerosolized antimicrobial particles is effective to sterilize thesurfaces of food products 13, the aerosolized particles may, withoutintervention, have a tendency to drift outside the walls 12 and adhereto unintended surfaces, including workers in the near vicinity of thesystem 10. In particular, particles are liable to escape through thepoints at which food products 13 enter and exit the cabinet, room,and/or chamber, as well as through unsealed gaps at the top of theinterior space surrounding the conveyor 14. This problem of unintendeddrift is solved by ensuring that the positively charged antimicrobialparticles pass through a negatively charged magnetic field. Asillustrated in FIG. 9, negatively charged electromagnets 15 a,b areprovided at various points along the walls 12. The electromagnets 15attract the positively charged antimicrobial particles, ensuring thatthe particles do not escape from the interior space defined by the walls12. In embodiments, electromagnets 15 may be side electromagnets 15 a,i.e. disposed on an interior surface of vertical walls 12, or they maybe overhead electromagnets 15 b, i.e. disposed on an interior surface ofa ceiling or roof of walls 12. No matter their placement, however,electromagnets 15 are oriented to impart a negative magnetic charge intothe interior space defined by walls 12. As a result of their attractionto electromagnets 15, the positively charged antimicrobial particleswill not drift toward gaps or holes by which they may escape into asurrounding environment. As antimicrobial particles are drawn towardelectromagnets 15, they are captured and removed from the interior spaceby air/particulate evacuation columns or ports 16.

It is to be expressly understood that the ability to control theenvironment in close proximity to an electrostatic antimicrobialtreatment application extends beyond applications in which a cabinet orother relatively small treatment enclosure is provided. By way ofnon-limiting example, electrostatic nozzles 11, electromagnets 15, andoptionally evacuation columns or ports 16 may be provided in a largeenclosure, such as a fixed food processing facility or a semi-trailertruck, or may even be provided outdoors. In outdoor embodiments, walls12 may merely be horizontal or vertical mounts, panels, or similarfeatures, provided (e.g. at a desired point of a conveyor 14) for thesole purpose of affixing electrostatic nozzles 11, electromagnets 15,and/or evacuation columns or ports 16 in a desired configuration. Thecombination of electrostatic nozzles 11, electromagnets 15, andoptionally evacuation columns or ports 16 enables precise control of theantimicrobial particles even in a large and/or outdoor space.

The invention illustratively disclosed herein suitably may be practicedin the absence of any element which is not specifically disclosedherein. It is apparent to those skilled in the art, however, that manychanges, variations, modifications, other uses, and applications of theinvention are possible, and also changes, variations, modifications,other uses, and applications which do not depart from the spirit andscope of the invention are deemed to be covered by the invention, whichis limited only by the claims which follow. By way of non-limitingexample, though the foregoing description of the invention has relatedto animal carcasses, systems and methods according to the invention maysterilize the surfaces of fruits and vegetables without departing fromthe spirit and scope of the invention. Likewise, by way of furthernon-limiting example, the negatively charged electromagnets as describedmay be replaced by static or rare-earth magnets without departing fromthe spirit and scope of the invention. Similarly, by way of additionalnon-limiting example, though the foregoing description of the inventionhas related to a positively charged aerosol spray and a negativelycharged electromagnet, those of ordinary skill in the art would be ableto understand and implement the converse, i.e. negatively chargedaerosol spray and positively charged electromagnets, without departingfrom the spirit and scope of the invention.

The foregoing discussion of the invention has been presented forpurposes of illustration and description. The foregoing is not intendedto limit the invention to the form or forms disclosed herein. In theforegoing Detailed Description of the Invention, for example, variousfeatures of the invention are grouped together in one or moreembodiments for the purpose of streamlining the disclosure. The featuresof the embodiments of the invention may be combined in alternateembodiments other than those discussed above. This method of disclosureis not to be interpreted as reflecting an intention that the claimedinvention requires more features than are expressly recited in eachclaim. Rather, as the following claims reflect, inventive aspects lie inless than all features of a single foregoing disclosed embodiment. Thus,the following claims are hereby incorporated into this DetailedDescription of the Invention, with each claim standing on its own as aseparate preferred embodiment of the invention.

Moreover, though the description of the invention has includeddescription of one or more embodiments and certain variations andmodifications, other variations, combinations, and modifications arewithin the scope of the invention, e.g. as may be within the skill andknowledge of those in the art, after understanding the presentdisclosure. It is intended to obtain rights which include alternativeembodiments to the extent permitted, including alternate,interchangeable, and/or equivalent structures, functions, ranges, orsteps to those claimed, whether or not such alternate, interchangeable,and/or equivalent structures, functions, ranges, or steps are disclosedherein, and without intending to publicly dedicate any patentablesubject matter.

1. A method for antimicrobial treatment of fruit food products,comprising: a) aerosolizing a liquid antimicrobial agent to formaerosolized antimicrobial particles; b) imparting a positive charge tothe aerosolized antimicrobial particles; c) spraying the aerosolizedantimicrobial particles into a treatment volume; d) placing at least onefruit food product at least partially within the treatment volume suchthat at least a first portion of the aerosolized antimicrobial particlesadheres to a surface of the at least one fruit food product to form asubstantially uniform layer of the antimicrobial agent; e) imparting anegative charge to at least one evacuation region within the treatmentvolume to attract at least a second portion of the aerosolizedantimicrobial particles into the at least one evacuation region; f)evacuating substantially all of the aerosolized antimicrobial particleswithin the evacuation region from the treatment volume; and g) whereinthe aerosolized antimicrobial particles have an average diameter of lessthan about 60 microns.
 2. The method of claim 1, wherein an attractiveforce between the surface of the at least one food product and the layerof the antimicrobial agent is equal to about 75 times the force ofgravity.
 3. A method for antimicrobial treatment of vegetable foodproducts, comprising: a) aerosolizing a liquid antimicrobial agent toform aerosolized antimicrobial particles; b) imparting a positive chargeto the aerosolized antimicrobial particles; c) spraying the aerosolizedantimicrobial particles into a treatment volume; d) placing at least onevegetable food product at least partially within the treatment volumesuch that at least a first portion of the aerosolized antimicrobialparticles adheres to a surface of the at least one vegetable foodproduct to form a substantially uniform layer of the antimicrobialagent; e) imparting a negative charge to at least one evacuation regionwithin the treatment volume to attract at least a second portion of theaerosolized antimicrobial particles into the at least one evacuationregion; f) evacuating substantially all of the aerosolized antimicrobialparticles within the evacuation region from the treatment volume; and g)wherein the aerosolized antimicrobial particles have an average diameterof less than about 60 microns.
 4. The method of claim 3, wherein anattractive force between the surface of the at least one food productand the layer of the antimicrobial agent is equal to about 75 times theforce of gravity.
 5. A method for antimicrobial treatment of bird foodproducts, comprising: a) aerosolizing a liquid antimicrobial agent toform aerosolized antimicrobial particles; b) imparting a positive chargeto the aerosolized antimicrobial particles; c) spraying the aerosolizedantimicrobial particles into a treatment volume; d) placing at least onebird food product at least partially within the treatment volume suchthat at least a first portion of the aerosolized antimicrobial particlesadheres to a surface of the at least one bird food product to form asubstantially uniform layer of the antimicrobial agent; e) imparting anegative charge to at least one evacuation region within the treatmentvolume to attract at least a second portion of the aerosolizedantimicrobial particles into the at least one evacuation region; f)evacuating substantially all of the aerosolized antimicrobial particleswithin the evacuation region from the treatment volume; and g) whereinthe aerosolized antimicrobial particles have an average diameter of lessthan about 60 microns.
 6. The method of claim 5, wherein an attractiveforce between the surface of the at least one food product and the layerof the antimicrobial agent is equal to about 75 times the force ofgravity.
 7. A method for antimicrobial treatment of a whole animalcarcass food product, comprising: a) aerosolizing a liquid antimicrobialagent to form aerosolized antimicrobial particles; b) imparting apositive charge to the aerosolized antimicrobial particles; c) sprayingthe aerosolized antimicrobial particles into a treatment volume; d)placing at least one whole animal carcass food product at leastpartially within the treatment volume such that at least a first portionof the aerosolized antimicrobial particles adheres to a surface of theat least one whole animal carcass food product to form a substantiallyuniform layer of the antimicrobial agent; e) imparting a negative chargeto at least one evacuation region within the treatment volume to attractat least a second portion of the aerosolized antimicrobial particlesinto the at least one evacuation region; f) evacuating substantially allof the aerosolized antimicrobial particles within the evacuation regionfrom the treatment volume; and g) wherein the aerosolized antimicrobialparticles have an average diameter of less than about 60 microns.
 8. Themethod of claim 7, wherein an attractive force between the surface ofthe at least one food product and the layer of the antimicrobial agentis equal to about 75 times the force of gravity.